Return bend for fin tubes



April 30, 1929- E. A. DEWALD. 1,710,811

RETURN BEND FOR FIN TUBES Filed Dec. 25, 1927 1 52-1. Fig.8.

Esta D'LQL W INVENTOR Q 7 BY (aw. r W

#44 ATTORNEYS Patented Apr. 30, 1929.

UNITED STA IPANY, OF NEW YORK,

RETURN BEND FOR FIN This invention relates to heataadiating devices of the type employed for cooling heated for example, as the liquefied retrigerating I ratus.

' of small diameter bent or coiled, but

The object of the invention is to rovide an apparatus of this kind employing t in tubing provided with radiating with the tubes being which may be built at a cost little greater than radiators formed of continuous tubing. To 'this end my improved fins which interfere heat-radiating apparatus is composed of a series of straight tubes extending between suitable supports with the ends of the adjacent tubes connected together by means of return bends connected to the ends of-the tubes by means of an improved joint which is readily completed with hand tools after the tubes are inserted in the supports.

The tubes forming the tube bank may be connected in any desired series-parallel arrangement to provide a flow path having the necessary length and cross section for the cooling efiect which it is desired to obtain.

In the accompanying drawings I have shown a complete radiating apparatus composed of three parallel units, each unit having six tubes connected in series.

In said drawings Figure 1 is a side elevation of the assembled radiator; j 5

Fig. 2 is an end view looking from the right of Fig. 1;

Fig. 3 is an enlarged sideview of one of the return bends, one side being shown in section; and

Figs. 1- and 5 are sectional views of modified forms ofjoints which may be employed in lieu of the joint shown in Fig. 3.

Referring to the drawings, the radiator is composed of two supporting plates 1 which are fixed in place in proper spaced relation on any suitable base. not shown. Extending radiating tubes 2, of which eighteen are shown in the drawing, the tubes belng arranged in three vertical rows of $12: each. The tubing which thin copper tubing of small diameter having a closely-wound spiral heat-radiating fin 4 attached to its outer surface. The tubes are may Iengtl I prefer to employ is a Application filed December 28, 1827. Serial Jim 242,045.

preferably formed in lengths than the distance between the two-sup 1, 1, so that the tube projects faces of the supports at each be originally formed rts beyond the outer end. The tubes but extends merely from inner face to inner face of the two supports.

The tubes may, however, be cut from continuous lengths of the thin tubing and the removed at each end to provide the necessary projecting ends for receiving the return bends 3. As shown in Fig. 3, the supports 1 consist of metal plates and the ends of the tubes are supported in holes in the plates,

TES PATENT OFFICE. EDWARD A. DEWALD, or mssmnou, 01110, ASBIGNOB T0 salmon-Russians c01 1- N. Y., A oonronarrou or DELAWARE;

slightly greater I of the desired 1, in which case the spiral fin is not extended to the extreme ends of the tubes which holes are of a. diameter on the inner face of the plates to accurately fit the tubes while on the outer face of the plates the holes are of larger diameter, thereby providing annular wedge-shaped recesses 6 between the walls of the tubes and the walls of the holes in which they are supported.

The ends of the tubes are provided with annular grooves 7 immediately beyond the outer face of the supporting plates 1, the grooves preferably being rolled into the tubes prior to the assembly. of the tubes in the supports 1. This operation may be readily performed while the tubes are in the finwinding machine by means of grooving rollers whereby the tube sections of proper length with their ends ready to receive the return bends, may be produced without additional cost.

Each return bend 3 consists of a U-shaped tubular member of a bore corresponding with the bore of the tubes and with its two legs spaced apart a distance corresponding to the spacing of the tubes in the supports. Each end of the return bend is enlarged to provide an inside diameter equal to the outside diameter of the tubes, the enlarged portion being of a depth to permit the bend to telescope over the ends of the tubes to a sufiicient extent for the edge of the bend to be crimped into the groove 7 as indicated at 9, and thereby form an interlocking joint between the tubes and the return bend. To facilitate the crimping of the bends into the tubes the metal cut away on four sides as indicated at 8 the v and may all be headed before form of joint of the groove 7.

: ends of the bends are slotted to a greater unit while the return the metal on each side of the notches to be drawn-together as the bead is formed, for which purpose an ordinary hand-operated crimping toolis quite sufficient.

In Fig. 3 the joint at the upper side of the figure is shown in elevation as it'appears after the crimping operation. In order to render the joints air-and-watcr-tight and also to unite the tubes rigidly in the support and reinforce the joints against separation under rough usage, each joint is surrounded with a ring 10 of solder which extends into the V-shaped annular opening 6 between the tube and the supporting plate, and also ex tends out'beyond the ends of the notches 8 in the ends of the return bends. After applying the solder it is preferably wiped to form a triangular fillet adhering along its radial surface to the face of the plate and completely closing the joint against leakage.

A radiator of any desired capacity may readily be made according to the present invention. The tube lengths are all uniform assembly.- The return ends likewise are all uniform and may .have their ends extended and edges slotted in the manner shown during the process of manufacture. The supporting plates are punched to fit the tubes and after the tubes are assembled in the plates they may be fastened together in any suitable manner, as, for instance, by bolts at the top and bottom which hold the arts assembled as a bends are being attached. After the return bends are attached in the manner shown the two manifolds 5 may be applied to the projecting ends of the upper and lower banks of tubes by means of similar joints or otherwise, as may be desired.

In Fig. 4: I have illustrated a modified wherein a bead 12 is provided on the projecting ends of the tubes instead In this form of joint the depth than in the previously described case and are slipped over the endsof the tubes and crimped over the beads as shown at 13. The joint is then soldered with a fillet of solder covering the joint and anchoring the tubes to the supporting pipe. The making of this type of joint will be greatly facilitated by.

enlarging the bends during the process of manufacture to rovide a shoulder at the point where the ead 13 comes, so that all that is necessary after the radiator is assembled is to bend down the ends of the projecting tongues between the slots with the hand crimping tool.- For this type of joint the beads at one end of the tubes-are formed after the tubes are assembled in the plates.

In Fig. 5 I have shown a further modified form of joint wherein the ends of the tubes are slotted and expanded to form a bead or shoulder 14; which fits into an annular groove 15 formed in the inner wall of the re turn bend. This joint maybe employed with advantage where the metal of the tubes is sufficiently elastic for the previously slotted and flared tube end to be contracted and thrust into the end of the return bend to expand of its own resiliency into interlocking engagement with the groove of the bend. A small fillet of solder is applied to this joint also. This joint may also be used where the metal of the bond is soft enough to be rolled down into engagement with the wall of the tube by a hand-manipulated tool without being slotted.

It will. be obvious that the joint between the tube sections and the return bends may be otherwise modified without departing from the spirit of the invention, the essential features of which are the mechanical interlocking of the tubes and bends in a manner readily accomplished with a hand tool and then reinforcing the joint with a soldered fillet or other sealin means applied in the manner defined in tie following claims.

I claim:

1. In a heat-radiating apparatus the combination of a series of straight tube sections having radiating fins, means for supporting said tube sections in substantially parallel arrangement, return bends connecting the adjacent ends of said tube sections to form a continuous flow path, interlocking parts on said tube sections and said bends for joining them together, and a fillet of solder enclosing said interlocking parts and adhering to the face of the adjacent support.

2. In an apparatus of the class described, the combination of a support, a tube section supported therein, a second tubular member in telescopic engagement therewith and means connecting said section, and said support, said means comprising 1nterlocking parts on said tube section and said tion between said tube section and said support, said soldered connection overlying and said member i member respectively, and a soldered connec-- sealing the joint betweenthe tube section and said tubular member.

3. In an apparatus-of the class described, the combination" of a supporting bar having an opening, a tubular. member supported therein, a recess in said bar surrounding said member, a second tubular member in telescopic engagement with said first member and means connecting said members and said support comprising interlocking parts on said members, and a fillet of solder surrounding said interlocking parts and extending into the recess in said support.

t. In an apparatus of the class described, the combination of two telescoping tubular members, interlocking parts on said mem bers comprising a circumferential groove in one of said members, longitudinally extending tongues on the other of said members,

Ill

the combination of two telescoping tubular members, interlocking: parts on said members comprising a circumferential groove in one of said members, longitudinally extending tongues on the other of said members, said tongues being bent radially to project into said roove, and means for permanently sealing said parts together, said means com prising a ring of solder enclosing said inter locking parts and adhering to both said parts. In testimony whereof I aflix my signature.

' EDWARD A. DEWALD. 

